hvac trajectories toward zero
TRANSCRIPT
McHugh Energy Consultants
HVAC Trajectories toward Zero
Jon McHugh, McHugh Energy at WCEC Affiliate Forum
Western Cooling Efficiency Center Davis, CA May 7, 2013
CPUC Big Bold EE Strategies
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2019 T24 Adopted
2019 T24 In Effect
2019 T24 CASE
2016 T24 Adopted
2016 T24 In Effect 2016 T24
CASE Started
Residential ZNE-Ready Planning
2013 2014 2015 2016 2017 2018 2019 2013 2014 2015 2016 2017 2018 2019 2020
2013 T24 In Effect
2013-14 Program Yr Bridge
2015-17 PY 2018-?? PY
T-20 Ph-1
T-20 Ph-2
T-20 Ph-3
Scope for 2020 residential ZNE goal is single family and low rise multi-family Definition of ZNE includes plug loads, thus appliances are very important
Res NC ZNE
Begin with End in Mind.
AB 1109 50% reduction res lighting
energy
See “Code Driven Portfolios.” ACEEE 2012 Summer Study http://www.aceee.org/files/proceedings/2012/data/papers/0193-000177.pdf 3
T24 Part 6 – Energy Efficiency Standards
Executive Order B-18-12
AB 1109
Nonresidential Buildings Policy Timeline
2008 Title 24 in Effect
2013 Adopted
2011 2013 2015 2017 2019 2021 2023 2025 2027 2029
Warehouses 49 kBtu/sf* Small Office – 145
Retail - 149 College - 160 Lodging - 167
Schools 92 kBtu/sf
Large Office - 203 Health - 276
Ref Warehouse – 211 Food store - 447 Restaurant - 622
*Source energy kBtu/sf from CEUS CA Commercial End-Use Survey
50% of New State Buildings
ZNE
All New State Buildings
ZNE
2016 Adopted 2019
Adopted 2022 Adopted
2025 Adopted
2028 Adopted
All New Construction ZNE
50% Existing
Building Stock ZNE 25% indoor & outdoor lighting
reduction
Begin with End in Mind.
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Innovation: HVAC and Lighting Technology Trajectories
1990 1994 1998 2002 2006 2010 2014 2018 2022 2026
Required Economizer + FDD Econ Charge
FDD + Multi-speed VRF
VFD Fan
Evap Cond
SEER 10
SEER 13 SEER?
IEER??
Incand PAR
100 W Halogen
PAR 90 W HIR
PAR 75 W
CMH PAR 38 W
LED PAR 20 W
LED PAR 10 W
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California Climate Zones
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Coast: CZ’s 1, 3, 5, 6, 7 Near Coast CZ’s 2, 4, 8, 9 Inland Empire CZ 10 Central Valley CZ 11-13 Desert CZ 14 & 15 Mountains CZ 16
2013 Title Residential HVAC
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HERS verified duct sealing in all CZs. (§ 150.0(m)11)
Mandatory fan power and airflow testing OR Return duct design (Residential HVAC Quality Installation Improvements). (§150.0(m)13)
Prescriptive refrigerant testing and HERS verification
Duct insulation raised from R-4.2 to R-6.0 in climate zones 6, 7, and 8. (§150.1(c)9)
Whole house fan or Smart Vents and Night Breeze as alternatives in CZs 8-14. (§150.1(c)12)
Occupant Controlled Smart Thermostat as a tradeoff against the solar ready zone
2013 Title 24 Nonresidential Economizers Prescriptive threshold for economizers
lowered Moved from 75,000 Btuh down to 54,000
Btuh (4.5 tons) and > 1,800 cfm of airflow Removed exemptions related to computer
equipment and telecommunications Mandatory Fault Detection and
Diagnostics (FDD) All air-cooled unitary direct-expansion units
with an economizer and Mechanical cooling capacity >= 54,000 Btuh Applies to:
Packaged DX rooftops Split-systems Heat pumps Variable refrigerant flow systems
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Fans
Each system listed in Table 140.4-B shall be designed to vary the airflow rate as a function of actual load.
Variable Airflow Control of Fans
Cooling System Type Fan Motor Size Cooling Capacity Effective Date
Direct Expansion any >= 110,000 Btuh Jan 1, 2012
Direct Expansion any > 65,000 Btuh Jan 1, 2015
Chilled Water > ¼ hp any Jan 1, 2012
Evaporative > ¼ hp any Jan 1, 2012
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Prescriptive Requirements for Computer Rooms §140.9(a)
New process measure – similar to ASHRAE 90.1-2010 requirements
Air or water side economizers required for: Individual computer rooms > 5 tons cooling New systems in existing computer room > 50 tons cooling New system in a new room in existing bldg > 20 tons
Simultaneous heating and cooling prohibited Heating water to humidify air not allowed (non-adiabatic)
Use evaporative media or ultrasonic humidification (adiabatic) Fan system power ≤ 27 W/kBtuh at design conditions Fan speed control for DX > 5 tons and all chilled water
systems Fan power ≤ 50% design fan power at 66% of design fan speed. Simple payback < 5yr
Containment prevent recirculation (return from mixing with supply)
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2013 Title-24 Occupancy Controls
Occupancy sensors allowed as a control option for demand control ventilation
May reduce the ventilation rate to zero
One sensor per room Must do one hour pre-purge
prior to normal occupancy Must shut off outside air within
30 minutes of vacancy If single zone system, must
also cycle off the fan 11
Occupancy Sensing Thermostats Mandatory Occupancy sensor based HVAC control in:
Multipurpose rooms < 1000 sq ft Classrooms > 750 sq ft Conference rooms > 750 sq ft
Must automatically setup the cooling set point by 2°F or more and setback the heating temperature set point by 2˚F or more and ….
…Automatically reset the minimum required ventilation rate to zero or turn the supply fan off when the zone is unoccupied
Hotel/Motel Guestrooms Card key control or occupancy sensing controls to control:
thermostat, lights and half of the receptacles.
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Demand Responsive Communicating Thermostatic Controls
All unitary heating and/or cooling systems including heat pumps that are not controlled by a central energy management control system (EMCS) shall have an Overrideable Communicating Thermostat (OCST)
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2016 Key Residential HVAC and Envelope product development
Residential construction patterns that bring ducts out of unconditioned space and address code requirements concerning venting attics to prevent moisture
Construction methods that allow thicker exterior insulation while addressing moisture, durability and cost
Construction and design practices that increase wall thickness and decrease thermal bridging
Training and construction practices that are able to meet QII specs without taking significantly more time.
Fault Detection and Diagnostic (FDD) Equipment that can measure refrigerant charge and non-condensibles. FDD already required for nonres economizers
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Place Ducts in here
Batt or blown
insulation
Greater Comfort and Energy Savings via Improved Building Envelope
IAQ must be addressed to tighten envelope and properly ventilate
Bring ducts and sealed combustion equipment inside conditioned space
Feasible, reliable super-insulation
Compressorless comfort home
Envelope and building simulation
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Coastal Compressorless Comfort Home
Reduce loads enough so that AC is not needed Added envelope costs are partially offset by reduced HVAC system
costs. Not prohibiting AC but not required Justifies more insulation and better windows in mild CZs Justifies indirect evap cooling in hot climate zones Similar to basis of European Passive House Standard Must have good comfort model in CA Simulation Engine
Minimum LCC No Forced Air
System
No Ducts in UnConditioned Space Impacts HVAC equipment
Ducts in conditioned space or ductless HVAC Includes conditioned attics, scissor truss, other methods of
adding conditioned plenum space, and the use of ductless systems. Different methods of addressing heating in the conditioned space include sealed combustion furnaces, combined water heating and space heating and heat pumps.
Simulation of ducts in conditioned space group of measures conditioned attic space, ducts in conditioned spaces, ductless
systems, sealed combustion, combined heating and water heating and how does it impact efficiency of condensing water heaters.
VRF and CV mini-split Develop methodology and rating data needed to provide
accurate model of water heating for VRF.
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Res Ventilation
Controlled supply mechanical ventilation Evaluate the costs, the energy benefits and the air quality benefits
from replacing exhaust based ventilation with supply based ventilation
Heat recovery ventilation Evaluate whether heat recovery ventilators are cost-effective in the
more extreme climate zones and develop a proposal if so. This would replace the other mechanical ventilation requirements.
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Res HVAC Measures Dual path - higher HVAC efficiency in
alternative path include higher HVAC efficiency in
alternate path FDD/CID refrigerant
charge/condensables (2016?) Propose a requirement for FDD that
would verify proper refrigerant charge, lack of condensables in the system and proper airflow.
Evaporative cooling baseline hot/dry CZs Evaluate and develop and evaporative
cooling code baseline for homes in hot/dry climate zones
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Avoiding Preemption: Multiple Path Energy Codes
Photovoltaics or Large Impact
Efficiency Measure
Minimum Federal Efficiency Equipment
Other Common Efficiency Measures
Photovoltaics or Large Impact
Efficiency Measure
Minimum Federal Efficiency Equipment
Other Common Efficiency Measures
Prescriptive Paths Standard Path(s)
Performance (Software) Approach
At least one standard path for every alternate path with higher efficiencies
Reduced or no PV required or
other Eff Measure
Higher Efficiency Equipment than
Fed Min Eff
Other Common Efficiency Measures
Alternate Path(s)
See “Federal Appliance Standards Should be the Floor, Not the Ceiling…” ACEEE 2012 Summer Study http://www.aceee.org/files/proceedings/2012/data/papers/0193-000415.pdf 20
Dual Path Approach and BEARS
Dual path approach PV vs. high eff equipment PV in base case: trade-off with equip eff:
HVAC, water heating, refrigeration PV model offsets consumption
Performance method base case with PV and method for trade-offs
BEARS (Building Energy Asset Rating) System) whole building rating model including deemed plug loads. Evaluate plug load data from a number of
sources including CEUS and COMNET and incorporate into ACM so that performance runs also generates a BEARS design rating
ZNE: BEARS = 0
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Nonres HVAC measures Low W/sf HVAC systems
Limit connected HVAC connected load. Don't double count interlocked loads. Consider a fan efficiency requirement or W/cfm requirement
Heat recovery Heat recovery with thresholds by cfm of O/A and climate zone
ACM - Base Case HVAC rule set Performance rule set without exceptions (VAV reheat?), max W/sf,
validated EPlus algorithms, base case and proposed case when AC not used, comfort model. Economizer simulation model for two speed AC.
ACM - Improved and validated VRF simulation Rigorous method of incorporating VRF test data into simulation that
results in accurate estimate of energy impact. ACM - VAV w/reheat, integration with DCV, chilled beam and DCV.
Validate and improve Eplus simulation of nonresidential HVAC simulation types. Compare to eQUEST and rationalize or fix the discrepancies
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Advanced HVAC
Improved Natural Ventilation and displacement ventilation simulation Evaluate Eplus natural ventilation model and make
recommendations for the ACM. Evaluate the feasibility and cost-effectiveness of a natural ventilation and displacement ventilation base case by climate zone..
Radiant model including comfort Evaluate Eplus radiant heating/cooling model and make
recommendations for the ACM. Update Eplus model if necessary. Adjust setpoint temperatures based on ASHRAE 55 and operant temperature.
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Process - Fume Hoods & Computer Rooms Lab fume hoods, Occupancy sensing control
of sash Evaluate the feasibility and cost-effectiveness of
an automatic control of vent hood sashes. Similar to automatic doors at stores Requires VAV fume hood exhaust system
Lab HVAC measures reset general room airflow rate and setpoint when
unoccupied after hours, max W/cfm at peak air flow, no simultaneous heating and cooling (dual duct,
chilled beam, 4PFC etc.,), Internal gains in labs can vary widely over
time and they become the “rogue” zone sizing calculated, exhaust duct sealing.
Computer rooms Economizers on smaller equipment Measures applied to smaller computer
rooms and data centers
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Opportunities ahead
Aggressive goals for 2020, 2025 and 2030 $2.6 Billion for school energy upgrades over the next 5
years (2013-2018) Prop 39 Significant changes to 2013 Title 24
Significant niches in eff HVAC and controls Similar changes from ASHRAE 90.1 and IECC
New opportunities for 2016 codes Emphasis on individual measures
Incremental cost Energy savings Feasibility Enforceability (ratings etc.)
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